Universal grippers for tooling, fixtures and robotic end-effectors advantageously employ holding devices that attach to a variety of arbitrarily-shaped workpieces for movement and placement during manufacturing and assembly processes. Universal grippers may employ some form of external power to effect gripping and release, including vacuum-based suction grippers and anthropomorphic, multi-digit grippers for grasping and manipulating workpieces.
Passive universal grippers require minimal grasp planning and include components that passively conform to unique workpiece geometries, giving them the ability to grip widely varying workpieces without readjustment. Passive universal grippers may be simple to use and may require minimal visual preprocessing of their environment. However, an ability to grip many different workpieces often renders passive universal grippers inferior at gripping any one workpiece in particular.
One passive, universal jamming gripper employs granular materials contained in a pliable membrane that conforms to a surface of a workpiece by applying a jamming force. Such operation exploits temperature-independent fluid-like characteristics of the granular materials, which can transition to a solid-like pseudo-phase with application of a vacuum inside the pliable membrane. This type of gripper employs static friction from surface contact, capture of the workpiece by conformal interlocking, and vacuum suction when an airtight seal is achieved on some portion of the workpiece surface. A jamming gripper employs static friction from surface contact, capture of workpiece by interlocking, and vacuum suction to grip different workpieces of varying shape, weight and fragility in an open loop configuration without employing grasp planning, vision, or sensory feedback.